From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F40A7C04AB4 for ; Fri, 17 May 2019 16:03:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C6F802166E for ; Fri, 17 May 2019 16:03:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1558108982; bh=LdHS0dAPP+v3YwxrLzn34XUx+tjoIKpjeNmFXlCLv4k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=pjhbhskDaVqEsrgO5idOahFyd1yz5qVEUW/rPkV1BPzICxRbQWcgPKPOT9n6oRZbD 4LaMlfX6mJdeuKPYefblhk26dwXPV9ubpbzcYLdCjJMHJyJN9LnIWe1lPwaL1VioHw bXbOrWpezZwPBlLX3sT6i/mshi2H/v3Gpoew5CxI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728664AbfEQQC6 (ORCPT ); Fri, 17 May 2019 12:02:58 -0400 Received: from mga04.intel.com ([192.55.52.120]:62944 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728482AbfEQQC6 (ORCPT ); Fri, 17 May 2019 12:02:58 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 May 2019 09:02:57 -0700 X-ExtLoop1: 1 Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by fmsmga004.fm.intel.com with ESMTP; 17 May 2019 09:02:57 -0700 Date: Fri, 17 May 2019 09:57:43 -0600 From: Keith Busch To: "Rafael J. Wysocki" Cc: Linux PCI , Linux PM , Linux ACPI , LKML , Bjorn Helgaas , Mika Westerberg Subject: Re: [PATCH] PCI: PM: Avoid possible suspend-to-idle issue Message-ID: <20190517155743.GB25006@localhost.localdomain> References: <2315917.ZGeXE6pBFC@kreacher> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2315917.ZGeXE6pBFC@kreacher> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Fri, May 17, 2019 at 11:08:50AM +0200, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > If a PCI driver leaves the device handled by it in D0 and calls > pci_save_state() on the device in its ->suspend() or ->suspend_late() > callback, it can expect the device to stay in D0 over the whole > s2idle cycle. However, that may not be the case if there is a > spurious wakeup while the system is suspended, because in that case > pci_pm_suspend_noirq() will run again after pci_pm_resume_noirq() > which calls pci_restore_state(), via pci_pm_default_resume_early(), > so state_saved is cleared and the second iteration of > pci_pm_suspend_noirq() will invoke pci_prepare_to_sleep() which > may change the power state of the device. > > To avoid that, add a new internal flag, skip_bus_pm, that will be set > by pci_pm_suspend_noirq() when it runs for the first time during the > given system suspend-resume cycle if the state of the device has > been saved already and the device is still in D0. Setting that flag > will cause the next iterations of pci_pm_suspend_noirq() to set > state_saved for pci_pm_resume_noirq(), so that it always restores the > device state from the originally saved data, and avoid calling > pci_prepare_to_sleep() for the device. > > Fixes: 33e4f80ee69b ("ACPI / PM: Ignore spurious SCI wakeups from suspend-to-idle") > Signed-off-by: Rafael J. Wysocki LGTM Reviewed-by: Keith Busch